The Wellcome Trust in Thailand: malaria, rabies and snakebite (1987)

the Wellcome Trust supports five units in the tropics one of them is in Thailand in 1979 David Worrell and his wife married from the University of Oxford sent up a welcome unit at the Faculty of Tropical Medicine in the University of Bangkok working in close cooperation with the staff of the university studies have been made of malaria rabies and snakebite all important health problems in Thailand this is the bridge over the river kwai in northwest Thailand close by our opencast gem mines that produce some of the country's finest sapphires the workers here dig holes which fill with water in the rainy season and the stagnant pools become breeding places for mosquitoes that transmit a deadly form of malaria in its most severe form fall sipper of malaria is most common near the Cambodian and Burmese borders many recent immigrants who have no immunity become infected patients with cerebral malaria become unconscious and up to half of them die this man's reflexes show that his brain is severely affected studies have shown that the brain is short of oxygen probably because red blood cells containing parasites obstruct the small blood vessels this is an electron micrograph of a cross-section of a vessel from the brain of a patient who died from cerebral malaria the blue area is the outer wall and this is a blood cell with malaria parasites inside it so the blood vessel is obstructed this may explain why the brain is starved of oxygen and a patient is unconscious in these patients it is vital to give quinine intravenously and to give a large loading dose so that an effective blood level is reached quickly the Wellcome team also showed that the expensive anti-inflammatory drug dexamethasone that has been widely used in cerebral malaria did not improve survival but actually prolonged unconsciousness and caused complications rabies is another major health problem in Thailand it is estimated that 3 percent of Thai dogs have rabies and over the country more than 300 people died from the disease each year this woman has hydrophobia terror of water the most characteristic sign of rabies and careful itis which is always fatal at this Institute 15,000 Bangkok residents bitten by dogs come for vaccination against rabies each year sheeps brains containing inactivated virus are used to produce the vaccine this method has been used here since 1912 and is much the same as the vaccine used by Pasteur 100 years ago it is life-saving but it has to be given in long courses of large painful injections and side-effects are common the Wellcome unit has shown that the expensive but safe and potent tissue culture vaccines now used in the West can be used economically if injected into the skin at eight sites from which the main lymph drainage occurs less than one third of the usual dose is fully effective southern Thailand miles of rubber plantations and a venomous snake problem around dawn each day the rubber tappers moved swiftly along the rows of trees setting up their cups to collect the rising latex the tappers work barefoot although they are well aware that there are often dangerous snakes in the grass this boy was bitten six hours ago by a Malayan pit viper and you can see the marks made by its fangs fangs that are long and hinged this one is being milked of its venom for research purposes and there is enough venom here to kill several people our patient has massive blood blisters near the site of the bite he is bleeding from his gums and his blood does not clot this bump on his eyelid is a reaction to the unrefined anti-venom he's been given thanks to expert attention he will live but he will be very ill for several days and he may need skin grafts another victim has the fluid pressure and his swollen leg monitored by the welcome team so that surgical relief can be given if the pressure rises to endanger the blood supply in Thailand most deaths are caused by Cobras and crates are the equally dangerous snakes such as Malayan pit vipers Russell's Vipers and green pit vipers all give rise to severe disability identification of the snake is important so that the correct anti-venom can be given if the species of snake is not known venom in the blister or blood of the patient can be identified by a test developed in collaboration with workers from the Liverpool School of Tropical Medicine improved refined antivenoms are being made by combining specific monoclonal antibodies it should before long be possible to make vaccines by genetic engineering techniques to protect people most at risk from snakebite